System and Method for Data Input

1. A portable information or data device that allows a user to input data in the form of text or other information as a series of characters, text, numbers, punctuation, or other symbols, comprising: a touch sensitive screen for entry and display of the data; a plurality of control buttons within a region of the touch sensitive screen, and accessible by the touch of the screen, wherein each of said control buttons is associated with a single datum and with a set of secondary data entry buttons; a plurality of secondary data entry buttons, that replace some or all of the plurality of control buttons on the touch sensitive screen when one of the control buttons is selected, wherein each secondary data entry button represents a single datum; and, wherein the user can first select a control button, followed by selection of any of the secondary data entry buttons associated with that control button, to enter the represented datum into the portable information or data device and wherein said control buttons and said secondary data entry buttons represent all the letters of the alphabet and fewer than all such letters being displayable on said touch sensitive screen at any one time.

2. The portable information or data device of claim 1 , wherein the plurality of secondary data entry-buttons replace only some of the control buttons.

3. The portable information or data device of claim 1 , wherein the text, characters, numbers, and symbols entered appear on the touch sensitive screen and/or on a separate display area of the device.

4. A method of using a portable information or data device that allows a user to input data such as text or other information as a series of characters or other symbols, comprising the steps of: providing a touch sensitive display screen for entry and display of the data including a plurality of control buttons arranged within a region of the touch sensitive display screen, and accessible to the user by touch of the screen, wherein each of said control buttons is associated with a single datum and with a set of secondary data entry buttons; receiving by touch of the screen a user selection of one of said control buttons; displaying on said touch sensitive display screen, in response to said user selection of one of said control buttons, a secondary data entry input including a plurality of secondary data entry buttons, wherein each said secondary data entry button represents a single datum that by touch of the screen can be input into the system; receiving a user selection of one of said secondary data entry buttons; and entering into the portable information or data device the datum represented by the selected secondary data entry button.

5. The method of claim 4 , wherein the control buttons are comprised respectively of the vowels A, E, I, O, U, and the secondary data entry buttons for each such vowel are the consonants following each of said vowels and preceding the next vowel in the alphabet.

6. A method, according to claim 5 , further comprising displaying, in response to selective user inputs, all the letters of the alphabet on the touch sensitive display screen, in which fewer than all the letters are displayed at any one time.